Fuse.



P. H. WESTON, JR.

FUSE.

APPLICATION FILED APR. 10, 1902.

Patented July 19, 1910.

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wilfnesses ff# iz UNITED STATES PATENT OFFICE.

FREDERICK H. WESTON, JR., OFSGHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, .A CORPORATION OF NEW YORK.

FUSE.

Specification of Letters Patent.

Patented July 19, 1910..

Application led. April 10, 1902. Serial No. 102,258.

T o all whom it may concern:

Be-it known thatl L'FREDERICK H. WES- TON, Jr., a citizen of the United States, re-v siding at Schenectady, in the count-y of Schenectady, State of New York, have invented certain new and useful Improvements in Fuses, of which the following is a specification.

The object of this invention is to provide a fuse in which the certaintyA of extinguishment of the arc will be greater than with thermal cut-outs of types ordinarily employed.

Certain features of the invention may be adopted in fuses of any class, but the invention is especially applicable to those of the cartridge type, in which a fusible conductor or strip is inclosed in a containing shell.

My improvements consist in employing between the terminals a fuse length of curved, zigzag, serpentine, helical, spiral, or other devious contour, by which the path of the arc'stream is increased in length in comparison with the straight-line distance between the terminals; and in order to prevent the gaseous products, when the fuse melts or vaporizes, from arcing across so as to lfollou1 another path than that determined by the contour of the fuse. I provide barriers of some suitable form by which any tendency of the vapor to form such a different path is etfectually prevented.

I have found the best results to materialize by inclosing the fuse of irregular conformation in-an absorptive material,`vvhich is insulating and refractory, and preferably consisting Jof fragments of lcomparatively small subdivision. For this purpose I have obtained good results with lime, granular marble and similar products which are nonconductors of electricity, are very refractoryl to heat, and arel poor conductors of heat. Thus the products of the fuse when it -melts or vaporizes are driven .by the developed pressure into the pores or interst-ices of the porous material, cooling them and preventing the .arc from holding over; and in this tendency the increased length Qf the fuse between the terminals is of very reat assistance, the extinguishing effect eing much greater than with a fusewhich is inclosed in a finely divided non-conducting material and -which extends through the same in a straight line.

vMy fuse also embodies structural improvements in the terminals of the cartridge,

,both in point of cheapness and eect-iveness,

as will be hereinafter set forth.

The several features of novelty will be particularly described hereinafter and will be definitely indicated in the claims appended to thisl specification.

InA the accompanying drawings, which illustrate my invention, Figure l is a sectional elevationl of a cartridge fuse embodying my improvements; Fig. 2 is an end view of the same; Fig. 3 is a detail of the blank from which the terminal is formed; Fig. 4 shows a finished terminal; and Fig. 5 shows one form of fusible conductor and leads.

l -represents a shell of fiber or other suitable insulating material in tubular form. This is commonly made of some organic material, such as fiberby'reason of ease of manufacture. In order to prevent the heat of the fuse from damaging this casing, it is lined with a layer 2 of asbestos. 0n the ends of this shell are secured brass caps 543-311, heilig lagged fast by set-screws, as indicated. Each vcap is provided with one or more vent holes, as .ln-4a to prevent destruction of the cartridge in case of a shortcircuit on extraordinary and sudden rise of pressure due to instantaneous volatilization of the mass of fusiblematerial. The fuse itself may be formed of any suitable material, such as commonl fuse-metal formed of an alloy of lead and tin, or it may be made of'a strip of sheet zinc or sheet aluminum, or even sheet copper. The form shown in the-drawing at 5, is a lead-tin' fuse. This is soldered fast to lead wires 6-G, which may be formed of copper or other relatively less fusible material than the metal constitilting the fusestrip, which in turn at the free ends is connected with the copper terminals 7*78. These terminals are formed from a piece of sheet copper, a blank being first formed as indicated iii Fig. 3, and then folded in the middle as indicated in Fig. 4, the four ears 8 of the blank being bent at right angles.. to the plane of the terminal, as indicated in Fig. 4. At the time the blank is struck'lioles 9 are punched, which,

when the blank is bent, lie at a distance from the ears 8, depending on the thickness.

nals inserted, as shown in Fig. l, into the other cap, and fastened with a cotter pin..

The shell is'then filled with the granular or finely divided material used to surround the fuse, and the other cap slipped over the free terminal and the set-screws 'driven in so as tofasten the parts securely together.

The fuse shown in the drawings is a simple helix, the generating radius of which decreases near theends. This may be widely varied however, and the helix may be made of uniform diameter and may be made of varying pitch and of varying distance be tween the turns. The invention is however not limited to helical configuration, but may be of zigzag or undulating form, the several bends being in the same or differentplanes as may be desired. The essential feature is that the distance between the fixed copper leads or between the fuse terminals may be considerably increased by the bent or irregular shape of the fusible strip, forcing the arc, when the fuse melts, to traverse a much greater length in order to hold over than would be the case ifa straight fuse strip were employed. YVhen the fuse-blows, the melted or volatilized metal is driven by the pressure generated by heat and volatilization into the porous material, the increased length greatly increasing the resistance of the arc stream due to the unfused residual products in the contracted channel or path between the terminals. This increased resistance of course renders the arc less tenacious and .therefore contributes to its ex- -tinguishment I desire to have it understood that the several parts of the invention may be used separately if desired; for example, the improvements in the terminal may be used with straight fuses or fuses of any other kind; similarly the fuse may be usedv with any kind of terminals. y

In assembling the parts of the fuse one end-cap is removed and one of the termi- What vI claim as new and desire to secure by Letters Patent of the United States is,

1. The combination with an inclosing casing and an` absorbent filling materia-l, of a fusible member extending therethrough and provided with portions bent transversely to its axis and lying in a plurality of planes, whereby upon meltingl thereof a hydrostatic head is Vproduced at some point in the channel containing the molten metal.

2. A thermal cut-out comprising a sinuous strip of fusible metal, and a non-conducting absorbent material `surrounding said strip.

3. A thermal cut-out comprising a receptacle, a helically bent stri-p of fusible Inaterial within said receptacle, and a. nonconducting absorbent material carried Aby said receptacle and in contact with said strip.

4. A thermal cut-out colnprising a shell.

of insulating material provided at yits ends with metallic contacts, a helically bent or undulating strip of fusible material extending through said shell and connected to said terminals, and a filling of non-conducting absorbent material surrounding said strip.

5.A A cartridge fuse comprising la shell,

end-caps, terminals formed of sheet metal having bent lugs and adapted to be inserted from the inside of the cap, and a hole to receive a lock-pin after the parts have been assembled.

6. The combination with an inclosing casing, of a fuse link within the casing and having a terminal projecting through the wall of the casing and doubled over upon itself to form a rigid projecting fuse terminal.

7 The combination with a casing comprising a shell and a cap closing an .open end of the shell, of a fuse link within the casing and having a terminal projecting through the cap and doubled over upon itself to form a rigid projecting fuse ter- 'minal.

In witness whereof I have hereunto set my hand this'8th day of April, 1902.

. FREDERICK H. WESTON, JR.

Witnesses: i

BENJAMIN B. HULL, HELEN ORFORD. 

